Semiconductor Package Including Interposer with Through-Semiconductor Vias

ABSTRACT

The present application discloses various implementations of a semiconductor package including an organic substrate and one or more interposers having through-semiconductor vias (TSVs). Such a semiconductor package may include a contiguous organic substrate having a lower substrate segment including first and second pluralities of lower interconnect pads, the second plurality of lower interconnect pads being disposed in an opening of the lower substrate segment. The contiguous organic substrate may also include an upper substrate segment having an upper width and including first and second pluralities of upper interconnect pads. In addition, the semiconductor package may include at least one interposer having TSVs for electrically connecting the first and second pluralities of lower interconnect pads to the first and second pluralities of upper interconnect pads. The interposer has an interposer width less than the upper width of the upper substrate segment.

This application is a continuation-in-part of, and claims priority toand benefit of the filing date of a pending parent application entitled“Organic Interface Substrate Having Interposer withThrough-Semiconductor Vias,” Ser. No. 13/401,457, filed Feb. 21, 2012.The entire disclosure in that pending parent application is herebyincorporated fully by reference into the present application.

BACKGROUND

In semiconductor packaging, package substrates, also referred to asinterface substrates in the present application, are typically used tointerface one or more semiconductor dies to a support surface such as aprinted circuit board (PCB). Organic substrates have traditionally beenused and continue to be used as interface substrates in a variety ofpackaging designs, such as ball grid array (BGA) packaging, chip scalepackage (CSP) solutions, and system-in-package (SiP) solutions.

Organic interface substrates are fabricated according to strict designrules that can raise packaging costs where multiple contact pad pitchesare utilized. In addition, the minimum size of interconnect trace linewidths, line to line spacing, and contact pad pitch characterizingconventional organic interface substrates can make integration of dieswith high density input/output (I/O) arrays challenging.

SUMMARY

The present disclosure is directed to a semiconductor package includingan organic substrate and interposer having through-semiconductor vias(TSVs), substantially as shown in and/or described in connection with atleast one of the figures, and as set forth more completely in theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 presents a cross-sectional view of an exemplary semiconductorpackage using a conventional organic interface substrate.

FIG. 2A presents a cross-sectional view of an exemplary semiconductorpackage including an organic substrate and an interposer havingthrough-semiconductor vias (TSVs).

FIG. 2B presents a cross-sectional view of another exemplarysemiconductor package including an organic substrate and an interposerhaving TSVs.

FIG. 2C presents a cross-sectional view of an exemplary multi-diesemiconductor package including an organic substrate and an interposerhaving TSVs.

FIG. 2D presents a cross-sectional view of another exemplary multi-diesemiconductor package including an organic substrate and an interposerhaving TSVs.

FIG. 3A presents a cross-sectional view of an exemplary interfacesubstrate including an organic substrate and an interposer having TSVs,suitable for use in a semiconductor package.

FIG. 3B presents a cross-sectional view of an exemplary semiconductorpackage including the interface substrate of FIG. 3A mounted on asupport surface.

FIG. 3C presents a cross-sectional view of another exemplarysemiconductor package including an organic substrate and an interposerhaving TSVs.

FIG. 3D presents a cross-sectional view of an exemplary semiconductorpackage-on-package including an organic substrate and an interposerhaving TSVs.

FIG. 4 presents a cross-sectional view of an exemplary semiconductorpackage including an organic substrate and multiple interposers havingTSVs.

DETAILED DESCRIPTION

The following description contains specific information pertaining toimplementations in the present disclosure. The drawings in the presentapplication and their accompanying detailed description are directed tomerely exemplary implementations. Unless noted otherwise, like orcorresponding elements among the figures may be indicated by like orcorresponding reference numerals. Moreover, the drawings andillustrations in the present application are generally not to scale, andare not intended to correspond to actual relative dimensions.

FIG. 1 presents a cross-sectional view of an exemplary semiconductorpackage using a conventional organic interface substrate. FIG. 1includes semiconductor package 105 (or “package 105”) mounted on printedcircuit board (PCB) 190. Package 105 includes organic interfacesubstrate 100 and semiconductor device 140. Organic interface substrate100 includes a plurality of upper contact pads 112, with an exemplaryupper contact pad 112 explicitly identified as such. Organic interfacesubstrate 100 also includes a plurality of lower contact pads 114, withan exemplary lower contact pad 114 explicitly identified as such.

The plurality of lower contact pads 114 are coupled to a respectiveplurality of solder balls 115, with an exemplary solder ball 115explicitly identified as such. Semiconductor device 140 includes aplurality of microbumps 145, with an exemplary microbump 145 explicitlyidentified as such. The plurality of microbumps 145 are connected to theplurality of upper contact pads 112. Underfill 141 is situated belowsemiconductor device 140 to support and protect the plurality ofmicrobumps 145, as well as semiconductor device 140.

Organic interface substrate 100 may be a conventional multi-layerorganic substrate, functioning as an interconnection chip carrier forrouting input/output (I/O) pads on semiconductor device 140 to PCB 190,or another support surface. As noted above, an organic interfacesubstrate, such as organic interface substrate 100, is typicallyfabricated according to strict design rules. As a result, packagingcosts may become undesirably high where multiple contact pad pitches areutilized. Moreover, the minimum size of interconnect trace line widths,line to line spacing, and contact pad pitch characterizing conventionalorganic interface substrates can make integration of dies with highdensity I/O arrays challenging.

Referring to FIG. 2A, FIG. 2A presents a cross-sectional view of anexemplary semiconductor package including an organic substrate and aninterposer having through-semiconductor vias (TSVs). Semiconductorpackage 205 (or “package 205”) in FIG. 2A includes interface substrate200 mounted on PCB 290. Interface substrate 200 includes contiguousorganic substrate 210 having upper substrate segment 210 a and lowersubstrate segment 210 b and/or 210 c. It is noted with respect to theexemplary packaging implementations shown in FIGS. 2A, 2B, 2C, and 2D,that “lower substrate segment” may refer to either, or both, of thefeatures identified by reference numbers 210 b and 210 c. Interfacesubstrate 200 also includes interposer 230 embedded in contiguousorganic substrate 210.

Upper substrate segment 210 a has a lateral upper width 211, andincludes a plurality of upper contact pads 212, a first plurality ofupper interconnect pads 237, and a second plurality of upperinterconnect pads 238. Interposer 230 has a lateral interposer width 231less than upper width 211 of upper substrate segment 210 a. In addition,interposer 230 includes a plurality of TSVs 235, with an exemplary TSV235 explicitly identified as such. Lower substrate segment 210 b and 210c includes a first plurality of lower interconnect pads 233, a secondplurality of lower interconnect pads 234, and a plurality of lowercontact pads 214. The plurality of lower contact pads 214 are coupled toPCB 290 by a respective plurality of solder balls 215, with an exemplarysolder ball 215 explicitly identified as such.

Upper substrate segment 210 a and lower substrate segment 210 b and 210c may be fabricated of organic materials such as Bismaleimide-Triazine(BT), Ajinomoto Build-up Film (ABF), FR-4 laminates, E679-FBG,ECL4785GS, and E700. Upper substrate segment 210 a may utilize the samematerials as lower substrate segment 210 b and 210 c. Upper substratesegment 210 a and lower substrate segment 210 b and 210 c may eachinclude multiple conductive laminate or build-up layers for wiring, asknown in the art.

The first plurality of lower interconnect pads 233 may be electricallyconnected to the first plurality of upper interconnect pads 237 usingTSVs 235 to route the pads in any desired manner. An opening 201 dividesthe lower portion of contiguous organic substrate 210 into lowersubstrate segment 210 b and 210 c, and exposes the second plurality oflower interconnect pads 234. The second plurality of lower interconnectpads 234 may be utilized as lower contact pads, for example, to receivea lower semiconductor die (lower semiconductor die not shown in FIG.2A). The second plurality of lower interconnect pads 234 is capable ofelectrical connection to the second plurality of upper interconnect pads238 using TSVs 235.

The plurality of upper contact pads 212 of upper substrate segment 210 aare capable of electrical connection to the first and second pluralitiesof upper interconnect pads 237 and 238. For example, such electricalconnection may be established through use of conductive wiring layerswithin upper substrate segment 210 a that are not explicitly shown inFIG. 2A. Upper contact pads 212 may be implemented to receive an uppersemiconductor die (upper semiconductor die also not shown in FIG. 2A).

Interposer 230 may be fabricated of a semiconductor material such assilicon. As a result, TSVs 235 may be through-silicon vias. Because highdensity through-silicon vias may be utilized, interposer 230 may providea high density pad pitch for the first and/or second pluralities ofupper interconnect pads 237 and 238, as well as for the first and/orsecond pluralities of lower interconnect pads 233 and 234. Thus, thesecond plurality of lower interconnect pads 234 may have a pitch ofapproximately fifty micrometers (50 um) or less. As a more specificexample, the second plurality of lower interconnect pads 234 may have apitch of approximately 20 um to approximately 40 um, allowing a lowersemiconductor die with high density microbumps to be attached.Consequently, in one implementation, upper and lower semiconductor dieshaving different bump pitches may be supported by interface substrate200. Moreover, interface substrate 200 may be configured to receive alower semiconductor die with a high-density bump pitch less than, forexample, approximately 130 um.

In one implementation, upper substrate segment 210 a and lower substratesegment 210 b and 210 c may be fabricated separately. As a result,fabrication equipment may be matched to the requirements of eachsubstrate segment. Fabrication of upper substrate segment 210 a mayrequire equipment supporting a pad pitch of, for example, at least 130um for the plurality of upper contact pads 212. By contrast, fabricationof lower substrate segment 210 b and 210 c may only require equipmentsupporting a pad pitch of, for example, at least 300 um for theplurality of lower contact pads 214. In other words, a minimum pad pitchof upper substrate segment 210 a may be less than a minimum pad pitch oflower substrate segment 210 b and 210 c.

Continuing to FIG. 2B, FIG. 2B presents a cross-sectional view of anexemplary semiconductor package including an organic substrate and aninterposer having TSVs. Package 206 includes interface substrate 200 andupper semiconductor device 270, and is mounted on PCB 290. Uppersemiconductor device 270 includes a plurality of microbumps 275, with anexemplary microbump 275 explicitly identified as such. Underfill 271 issituated below upper semiconductor device 270 to support and insulatethe plurality of microbumps 275.

With respect to the detailed features of interface substrate 200, it isnoted that interface substrate 200 in FIG. 2B, as well as subsequentFIGS. 2C and 2D, corresponds to interface substrate 200 in FIG. 2A. Inother words, interface substrate 200 in FIGS. 2B, 2C, and 2D include thefeatures previously attributed to interface substrate 200 by referenceto FIG. 2A above. Moreover, it is reiterated that interposer 230 ofinterface substrate 200 has interposer width 231 less than upper width211 of upper substrate segment 210 a.

Upper substrate segment 210 a includes the plurality of upper contactpads 212 for receiving upper semiconductor device 270, which, accordingto the implementation shown in FIG. 2B is configured as a flip-chip.However, in other implementations, upper semiconductor device 270 mayinclude a wire-bonded die, and corresponding upper contact pads orfingers for the wire bonds may be provided on upper substrate segment210 a. Furthermore, while only a single upper semiconductor device 270is shown in FIG. 2B, alternative implementations may mount multiplesemiconductor devices onto the top surface of interface substrate 200.Thus, package 206 may be a hybrid package including both flip-chip andwire-bonded dies. Heat sinks and/or mold compound may also be applied topackage 206, but are not shown in FIG. 2B. Accordingly, package 206enables significant design flexibility through the capability ofaccommodating one or more semiconductor dies for connection to PCB 290through interface substrate 200.

Moving to FIG. 2C, FIG. 2C presents a cross-sectional view of anexemplary multi-die semiconductor package including an organic substrateand an interposer having TSVs. Package 207 of FIG. 2C may correspond topackage 206 of FIG. 2B with the addition of lower semiconductor device250. Lower semiconductor device 250 includes die contact pads 252, and aplurality of microbumps 255, with an exemplary microbump 255 explicitlyidentified as such. Underfill 251 is situated between lowersemiconductor device 250 and interposer 230 to support and protect theplurality of microbumps 255.

The plurality of solder balls 215 for connection of interface substrate200 to PCB 290 may be extended to include additional solder ballsconnected to die contact pads 252 of lower semiconductor device 250. Itis noted that although the plurality of solder balls 215 are all shownto have a substantially uniform size in FIG. 2C, the solder ballsconnected to die contact pads 252 and the solder balls connected tolower contact pads 214 may be of different sizes. For example, lowersemiconductor device 250 may extend beyond lower substrate segment 210 band 210 c, thereby necessitating smaller solder balls for die contactpads 252. Additionally, in some implementations, land grid arrays (LGAs)may be utilized instead of ball grid arrays (BGAs).

In some implementations, die contact pads 252 may be electricallyinactive and provided for thermal dissipation only. Multiplesemiconductor device dies may also be mounted onto the exposed bottomsecond plurality of lower interconnect pads 234 of lower substratesegment 210 b and 210 c, rather than only a single lower semiconductordevice 250 as shown in FIG. 2C. Heat sink/heat spreader and/or moldcompound may also be integrated into package 207, but are not shown inFIG. 2C.

As previously noted, because TSVs 235 of interposer 230 enable use ofhigh-density contact pads having a pitch of, for example, approximately20 um to approximately 40 um, upper and lower semiconductor dies withdifferent contact pad densities may be readily supported. Accordingly,package 207 may support multiple dies of different pitches, includinghigh-density pitches, for connection to PCB 290 through interfacesubstrate 200. For example, upper semiconductor device 270 may have amicrobump pitch of approximately 130 um to approximately 300 um, whereaslower semiconductor device 250 may have a microbump pitch ofapproximately 20 um to approximately 40 um. Moreover, package 207 may beconstructed in a cost effective manner using well known organicsubstrate fabrication techniques and fabrication equipment tailoredindividually to the pitch requirements of the separate upper and lowerorganic substrate layers.

FIG. 2D presents a cross-sectional view of another exemplary multi-diesemiconductor package including an organic substrate and an interposerhaving TSVs. With respect to FIG. 2D, package 208 differs from package207, in FIG. 2C only in the decoupling of lower semiconductor device 250from PCB 290. Thus, as shown in FIG. 2D, lower semiconductor device 250may not necessarily connect to PCB 290. Moreover, and as noted above,lower semiconductor device 250 may extend beyond lower substrate segment210 b and 210 c, as shown in FIG. 2D.

Referring now to FIG. 3A, FIG. 3A presents a cross-sectional view ofexemplary interface substrate 300 including contiguous organic substrate310 and interposer 330 having TSVs 335. Interface substrate 300 includescontiguous organic substrate 310 having upper substrate segment 310 aand/or 310 b, and lower substrate segment 310 c. It is noted withrespect to the implementations shown in FIGS. 3A, 3B, 3C, and 3D, that“upper substrate segment” may refer to either, or both, of the featuresidentified by reference numbers 310 a and 310 b. Interface substrate 300also includes interposer 330 embedded in contiguous organic substrate310.

Lower substrate segment 310 c has a lateral lower width 311, andincludes a plurality of lower contact pads 314, a first plurality oflower interconnect pads 333, and a second plurality of lowerinterconnect pads 334. Interposer 330 has a lateral interposer width 331less than lower width 311 of lower substrate segment 310 c. In addition,interposer 330 includes a plurality of TSVs 335, with an exemplary TSV335 explicitly identified as such. Upper substrate segment 310 a and 310b includes a first plurality of upper interconnect pads 337, a secondplurality of upper interconnect pads 338, and a plurality of uppercontact pads 312.

Upper substrate segment 310 a and 310 b, and lower substrate segment 310c may utilize the same materials as previously described with referenceto the substrate segments shown in FIGS. 2A, 2B, 2C, and 2D. That is tosay, upper substrate segment 310 a and 310 b, and lower substratesegment 310 c may be formed of BT, ABF, FR-4 laminates, and the like.Moreover, upper substrate segment 310 a and 310 b, and lower substratesegment 310 c may each include multiple conductive laminate or build-uplayers for wiring.

The first plurality of lower interconnect pads 333 may be electricallyconnected to the first plurality of upper interconnect pads 337 usingTSVs 335 to route the pads in any desired manner. An opening 301 dividesthe upper portion of contiguous organic substrate 310 into uppersubstrate segment 310 a and 310 b, and exposes the second plurality ofupper interconnect pads 338. The second plurality of upper interconnectpads 338 may be utilized as upper contact pads, for example, to receivean upper semiconductor die (upper semiconductor die not shown in FIG.3A). The second plurality of upper interconnect pads 338 is capable ofelectrical connection to the second plurality of lower interconnect pads334 using TSVs 335.

The plurality of upper contact pads 312 of upper substrate segment 310 aand 310 b are capable of electrical connection to the first and secondpluralities of upper interconnect pads 337 and 338. For example, suchelectrical connection may be established through use of conductivewiring layers within upper substrate segment 310 a and 310 b that arenot explicitly shown in FIG. 3A. Upper contact pads 312 may beimplemented to receive an upper semiconductor die or package (uppersemiconductor die or package also not shown in FIG. 3A).

Like interposer 230 described above, interposer 330 may be fabricated ofa semiconductor material such as silicon. As a result, TSVs 335 may bethrough-silicon vias capable of providing a high density pad pitch forthe first and/or second pluralities of upper interconnect pads 337 and338, as well as for the first and/or second pluralities of lowerinterconnect pads 333 and 334. For example, the second plurality ofupper interconnect pads 338 may have a pitch of approximately 50 um orless, such as a pitch of approximately 20 um to approximately 40 um.

Upper substrate segment 310 a and 310 b, and lower substrate segment 310c may be fabricated separately. As a result, fabrication equipment maybe matched to the requirements of each substrate segment. Fabrication ofupper substrate segment 310 a and 310 b may require equipment supportinga pad pitch of, for example, at least 130 um for the plurality of uppercontact pads 312. By contrast, fabrication of lower substrate segment310 c may only require equipment supporting a pad pitch of, for example,at least 300 um for the plurality of lower contact pads 314. In otherwords, a minimum pad pitch of upper substrate segment 310 a and 310 bmay be less than a minimum pad pitch of lower substrate segment 310 c.

Continuing to FIG. 3B, FIG. 3B presents a cross-sectional view of anexemplary semiconductor package including interface substrate 300mounted on PCB 390. Semiconductor package 305 (or “package 305”) showsinterface substrate 300 being mounted onto PCB 390 by solder balls 315,with an exemplary solder ball 315 explicitly identified as such. Withrespect to the detailed features of interface substrate 300, it is notedthat interface substrate 300 in FIG. 3B, as well as subsequent FIGS. 3Cand 3D, corresponds to interface substrate 300 in FIG. 3A. In otherwords, interface substrate 300 in FIGS. 3B, 3C, and 3D include thefeatures previously attributed to interface substrate 300 by referenceto FIG. 3A above. Moreover, it is reiterated that interposer 330 ofinterface substrate 300 has interposer width 331 less than lower width311 of lower substrate segment 310 c.

FIG. 3C presents a cross-sectional view of another exemplarysemiconductor package including an organic substrate and an interposerhaving TSVs. Package 306 includes interface substrate 300 and uppersemiconductor device 370, and is mounted on PCB 390. Upper semiconductordevice 370 includes a plurality of microbumps 375, with an exemplarymicrobump 375 explicitly identified as such. Underfill 371 is situatedbelow upper semiconductor device 370 to support and insulate theplurality of microbumps 375.

Opening 301 exposes the second plurality of upper interconnect pads 338(as shown in FIG. 3A), which may function as upper contact pads forreceiving upper semiconductor device 370. Upper semiconductor device 370is shown to have a flip-chip configuration in the implementation of FIG.3C. However, in other implementations, upper semiconductor device 370may include a wire-bonded die, and corresponding upper contact pads orfingers for the wire bonds may be provided on upper substrate segment310 a and 310 b.

Continuing to FIG. 3D, FIG. 3D presents a cross-sectional view of anexemplary semiconductor package-on-package including an organicsubstrate and an interposer having TSVs. Package 307 of FIG. 3D maycorrespond to package 306 of FIG. 3C with the addition of upper package380. Upper package 380 includes a plurality of solder balls 385, with anexemplary solder ball 385 explicitly identified as such. Thus, apackage-on-package solution may be provided, with package 306 as thelower package and upper package 380 as the upper package. Upper package380 may be any type of package, including a multi-die package.

Advantageously, because solder balls 385 may rest on an elevated surfaceprovided by interface substrate 300, the size of solder balls 385 may bereduced while providing sufficient vertical clearance for upper package380. Such a use of smaller solder balls 385 enables a reduced pitchsize. Thus, the overall height of the package-on-package structure ofpackage 307 may be reduced. As with the previous packaging examples,package 307 may optionally include a heat-sink and mold compound, whichis omitted from FIG. 3D.

FIG. 4 presents a cross-sectional view of an exemplary semiconductorpackage including an organic substrate and multiple interposers havingTSVs. Semiconductor package 405 (or “package 405”) includes interfacesubstrate 400 mounted on PCB 490. Interface substrate 400 includescontiguous organic substrate 410 having upper substrate segment 410 aand lower substrate segment 410 b. Interface substrate 400 also includesfirst interposer 430 a and second interposer 430 b, both of which areshown to be embedded in contiguous organic substrate 410. According tothe present exemplary implementation, contiguous organic substrate 410has a lateral width 411.

Lower substrate segment 410 b includes first group of lower interconnectpads 433 under first interposer 430 a, with an exemplary one of firstgroup of lower interconnect pads 433 explicitly identified as such.Lower substrate segment 410 b also includes second group of lowerinterconnect pads 434 under second interposer 430 b, with an exemplaryone of second group of lower interconnect pads 434 explicitly identifiedas such. In addition, lower substrate segment 410 b includes a pluralityof lower contact pads 414 coupled to a respective plurality of solderballs 415, with an exemplary solder ball 415 explicitly identified assuch.

Upper substrate segment 410 a includes first group of upper interconnectpads 437 over first interposer 430 a, with an exemplary one of firstgroup of upper interconnect pads 437 explicitly identified as such.First interposer 430 a has a lateral first interposer width 431 a and isinset by a distance 439 a from an outer lateral edge of contiguousorganic substrate 410. In addition, first interposer 430 a includesfirst set of TSVs 435 a, with an exemplary one of first set of TSVs 435a explicitly identified as such.

Upper substrate segment 410 a also includes second group of upperinterconnect pads 438 over second interposer 430 b, with an exemplaryone of second group of upper interconnect pads 438 explicitly identifiedas such. Second interposer 430 b has a lateral second interposer width431 b and is offset by a distance 439 b from an opposite outer lateraledge of contiguous organic substrate 410. In addition, second interposer430 b includes second set of TSVs 435 b, with an exemplary one of secondset of TSVs 435 b explicitly identified as such. One or both of firstand second interposers 430 a and 430 b may be fabricated of asemiconductor material such as silicon. As a result, one or both offirst and second sets of TSVs 435 a and 435 b may be through-siliconvias.

As described above, first group of lower interconnect pads 433 isdisposed under first interposer 430 a, and second group of lowerinterconnect pads 434 is disposed under second interposer 430 b. Asfurther described above, first group of upper interconnect pads 437 isdisposed over first interposer 430 a, and second group of upperinterconnect pads 438 is disposed over second interposer 430 b. Firstgroup of lower interconnect pads 433 may be electrically connected tofirst group of upper interconnect pads 437 using first set of TSVs 435 ato route the pads in any desired manner. Similarly, second group oflower interconnect pads 434 may be electrically connected to secondgroup of upper interconnect pads 438 using second set of TSVs 435 b toroute the pads as desired.

Moreover, as shown by FIG. 4, at least one of first group of upperinterconnect pads 437 is directly connected to at least one of secondgroup of upper interconnect pads 438 through upper substrate segment 410a. According to the implementation of FIG. 4, such a direct connectionis provided by wiring 412, which may be established using multipleconductive laminate or build-up layers of substrate segment 410 a.

Package 405 also includes first flip-chip 440 a mounted over firstinterposer 430 a, and second flip-chip 440 b mounted over secondinterposer 430 b. As shown in FIG. 4, first flip-chip 440 a is mountedover first interposer 430 a using microbumps 448 a, with one ofmicrobumps 448 a explicitly identified as such. Die attach material 446a is situated below first flip-chip 440 a to support and insulatemicrobumps 448 a. Second flip-chip 440 b may be similarly mounted oversecond interposer 430 b using microbumps 448 b, with one of microbumps448 b explicitly identified as such Die attach material 446 b may bedisposed below second flip-chip 440 b to support and insulate microbumps448 b.

According to the implementation of FIG. 4, distance 439 b is less thandistance 439 a. However, in other implementations, distance 439 b may begreater than, or substantially equal to, distance 439 a. Moreover,although first interposer width 431 a is represented as less than secondinterposer width 431 b in FIG. 4, in other implementations, firstinterposer width 431 a may be greater than, or substantially equal to,second interposer width 431 b. However, the sum of first interposerwidth 431 a and second interposer width 431 b is less than width 411 ofcontiguous organic substrate 410.

Upper substrate segment 410 a and lower substrate segment 410 b may befabricated of organic materials such as BT, ABF, FR-4 laminates,E679-FBG, ECL4785GS, and E700. Upper substrate segment 410 a may utilizethe same materials as lower substrate segment 410 b. In addition, asnoted above, upper substrate segment 410 a and lower substrate segment410 b may each include multiple conductive laminate or build-up layersfor wiring.

Upper substrate segment 410 a and lower substrate segment 410 b may befabricated separately. As a result, fabrication equipment may be matchedto the requirements of each substrate segment. Accordingly, fabricationcosts may be reduced in comparison to fabrication of a conventionalorganic substrate, where strict design rules may dictate the requiredfabrication equipment for substantially all layers of the interfacesubstrate.

Thus, as demonstrated by the above examples, the use of one or moreinterposers having TSVs enables the continued use of low cost and widelydeployed organic substrates in the fabrication of high densitysemiconductor packages. By providing a contiguous organic substrateincluding one or more embedded interposers, one or more semiconductordies may be attached to exposed interconnect pads coupled to TSVs formedin the interposer(s). Such a configuration enables the use of flip-chipswith high-density microbump arrays and the accommodation of dies withvaried bump pitches. In addition, the contiguous organic substrateincluding one or more embedded interposers can be used to implement apackage-on-package structure.

From the above description it is manifest that various techniques can beused for implementing the concepts described in the present applicationwithout departing from the scope of those concepts. Moreover, while theconcepts have been described with specific reference to certainimplementations, a person of ordinary skill in the art would recognizethat changes can be made in form and detail without departing from thescope of those concepts. As such, the described implementations are tobe considered in all respects as illustrative and not restrictive. Itshould also be understood that the present application is not limited tothe particular implementations described above, but many rearrangements,modifications, and substitutions are possible without departing from thescope of the present disclosure.

1-14. (canceled)
 15. A semiconductor package comprising: a contiguousorganic substrate including a first group of lower interconnect padsunder a first interposer, and a second group of lower interconnect padsunder a second interposer; a first group of upper interconnect pads oversaid first interposer, and a second group of upper interconnect padsover said second interposer; said first interposer including a first setof through-semiconductor vias (TSVs) for electrically connecting saidfirst group of lower interconnect pads to said first group of upperinterconnect pads; said second interposer including a second set ofthrough-semiconductor vias (TSVs) for electrically connecting saidsecond group of lower interconnect pads to said second group of upperinterconnect pads.
 16. The semiconductor package of claim 15, furthercomprising a first flip-chip mounted over said first interposer, and asecond flip-chip mounted over said second interposer.
 17. Thesemiconductor package of claim 15, wherein at least one of said firstinterposer and said second interposer comprises silicon.
 18. Thesemiconductor package of claim 15, wherein a first interposer width ofsaid first interposer is less than a second interposer width of saidsecond interposer.
 19. The semiconductor package of claim 15, wherein asum of a first interposer width of said first interposer and a secondinterposer width of said second interposer is less than a width of saidcontiguous organic substrate.
 20. The semiconductor package of claim 15,wherein at least one of said first group of upper interconnect pads isdirectly connected to at least one of said second group of upperinterconnect pads.
 21. A semiconductor package comprising: a contiguoussubstrate including a first group of lower interconnect pads under afirst interposer, and a second interposer; a first group of upperinterconnect pads over said first interposer; said first interposerincluding a first set of through-semiconductor vias (TSVs) forelectrically connecting said first group of lower interconnect pads tosaid first group of upper interconnect pads.
 22. The semiconductorpackage of claim 21, further comprising a first flip-chip mounted oversaid first interposer.
 23. The semiconductor package of claim 22,further comprising a second flip-chip mounted over said secondinterposer.
 24. The semiconductor package of claim 21, wherein at leastone of said first interposer and said second interposer comprisessilicon.
 25. The semiconductor package of claim 21, wherein a firstinterposer width of said first interposer is less than a secondinterposer width of said second interposer.
 26. The semiconductorpackage of claim 21, wherein a sum of a first interposer width of saidfirst interposer and a second interposer width of said second interposeris less than a width of said contiguous organic substrate.
 27. Asemiconductor package comprising: a contiguous substrate including afirst group of lower interconnect pads under a first interposer, and asecond interposer; a first group of upper interconnect pads over saidfirst interposer, and a second group of upper interconnect pads oversaid second interposer; said second interposer includingthrough-semiconductor vias (TSVs) for providing electrically connectionsto said second group of upper interconnect pads.
 28. The semiconductorpackage of claim 27, further comprising a first flip-chip mounted oversaid first interposer, and a second flip-chip mounted over said secondinterposer.
 29. The semiconductor package of claim 27, wherein at leastone of said first interposer and said second interposer comprisessilicon.
 30. The semiconductor package of claim 27, wherein a firstinterposer width of said first interposer is less than a secondinterposer width of said second interposer.
 31. The semiconductorpackage of claim 27, wherein a sum of a first interposer width of saidfirst interposer and a second inter-poser width of said secondinterposer is less than a width of said contiguous organic substrate.32. The semiconductor package of claim 27, wherein at least one of saidfirst group of upper interconnect pads is directly connected to at leastone of said second group of upper interconnect pads.